1. Field of the Invention
The present invention relates to locks and more particularly, to a combination-changeable complex lock.
2. Description of the Related Art
Conventional locks include two types, namely, the combination lock and the pin tumbler lock. If a combination lock is used, the user must enter the correct combination to open the lock. If a pin tumbler lock is used, the user must insert the key into the keyway of the pin tumbler lock and then rotate the plug of the pin tumbler lock with the key to the unlocking position so that the lock can be opened.
If a combination lock is used and the user forgets the correct combination of the combination lock, the user must deliver the lock to the distributor or a locksmith to open the combination lock. If a pin tumbler lock is used and the user does not have the key in hand, the user still fail to open the lock.
Further, a common combination lock usually does not provide a function of change of the combination, and thus the combination of the common combination lock is unchangeable. If the set combination of a combination lock is simple, a malicious person may crack the combination easily to open the combination lock. If the user writes down the combination on a memo or notebook to prevent forgetting the combination, a malicious person may steal the combination to open the lock, resulting in great loss of the user.